Programming with an eye towards scalability is desirable, but it can also be very limiting.
The truth is that 95% of sites will never need to worry about scalability. Unless you plan to have more than 10,000 pages on your site (such as might be accumulated by collecting lots of user generated content), I wouldn't worry about scalability. Just choose your platform and be happy. If your site is not performing well, there are usually caching plugins that can be installed, or you could upgrade to a more powerful host.
Sites with millions of monthly visitors and lots of pages are the ones that need to start worrying about scalability. If your site gets to that size unexpectedly, it is almost always possible to migrate to a scalable platform.
Worrying about scalability before you need to is a form of premature optimization. It will prevent you from using the easiest tools to get the job done and may prevent you from getting started at all.
Just launch your site and see what happens first. I have sites on Wordpress, and that works fine for them. It works fine for hundreds of thousands of other sites. I also have a site that gets enough visitors that it needs a load balancer, and fancy caching algorithms to keep it running. I started that site as static HTML.